1. Field of the Invention
The present invention relates to an information code which displays information by combining a plurality of wavelength characteristics such as colors, and a reader for reading the same.
2. Description of the Related Art
Information codes such as barcodes are simple in printing and easy in reading, and therefore they are in widespread use as information display means for commodities and the like.
The barcodes are classified into various types, such as the JAN code, the standard ITF, the CODE=138, the CODE=39, and the NW-7 code, which are displayed in respective specific forms. According to the display form of the JAN code which is in wide use in Japan, seven black and white bars are combined to form one module representative of one numeral, and the 13 modules thus formed are arranged to represent 13-digit numerals. In the 13-digit numerals, the first two-digit numerals represent a national number, the next five-digit numerals a manufacturer number, and the following five-digit numerals a commodity number, respectively, and the final-digit numeral is for use in checking.
In the JAN code, only the 13-digit numerals can be represented, and hence only the five-digit numerals are allotted to display commodities. In recent days, however, commodities have been classified into more various types and packaged in smaller quantities, and therefore it is sometimes difficult to register all the commodities which a single store deals in. As a result, registering new commodities requires deletion of old commodity registrations which are unnecessary any more.
Such lack of displayable information quantity becomes significant as the field in which the barcode is employed spreads. For instance, a telephone company issues a phone call statement in which the lack of the displayable information quantity is augmented by printing both a long barcode which is increased in number of bars and a standard type barcode arranged in parallel. In this method of arranging a plurality of barcodes, the following problems can arise: That is, the barcodes can strongly oppress a display surface in which letters are printed, to thereby mar the appearance; a prolonged barcode is prone to be omitted when read by a hand scanner; and this method is available only if a large display space is secured. As a result, this method cannot be a radical solution to the problem.
Further, a new usage of the barcode, such as in sales management and commodity management, has been considered by displaying, in one lump, a date of manufacture, a name of a manufacturer, a date of packing, and a shelf life. In this usage, when a purchaser of the commodity makes payment, these information items are read and recorded. However, insofar as a monochromatic barcode (which means a single color is used over a ground color, such as black and white, or red and white) is employed to display such a large quantity of information items, the display pattern can be unfavorably complicated and a barcode label can be upsized, whereby the resulting barcode is rendered impractical.
Still further, another usage of the barcode, such as in manufacturing management of industrial products, has been considered by not only applying simple information tags on component parts or products to be managed but also applying an information code which displays detailed information items, such as a production history and an inspection result, by means of information codes. This is for acquiring detailed information of the component parts or the products, on the manufacturing site or on the shipping site without inquiring to a control system using a host computer, etc.
However, in this usage as well, it has been difficult to create a practical system because of limit of the displayable information quantity assigned to the monochromatic information code.
It is therefore a first object of the present invention to provide an information code which is capable of displaying a largely increased quantity of information without changing conventional display patterns.
It is a second object of the invention to provide a reader for such an information code.
The information code according to the present invention is formed by arranging three or more types of display areas in a predetermined arrangement, the display areas being different in reflected or radiated wavelength characteristic, wherein the wavelength characteristics of the display areas in the predetermined arrangement are combined to form a unit for displaying information.
Herein, the terms xe2x80x9cbeing different in reflected or radiated wavelength characteristicxe2x80x9d means that the display areas in the predetermined arrangement to form the information code are different in color, and that when the information code is formed into a stealth code using fluorescent materials, the fluorescent materials printed in the display areas are different in emitted wavelength. Further, the terms xe2x80x9cthree or more types of display areas (are) different in reflected or emitted wavelength characteristicxe2x80x9d means that three or more types of display areas with respectively different wavelength characteristics are provided. If the display areas which are different in size and shape are used, the number of types of the display areas is equal to the number of combinations between the sizes and the shapes.
When the information code according to the present invention is intended to be used by replacing an existing monochromatic information code, it is difficult to smoothly switch to the information code of the present invention if the number of companies adopting the existing information code is extremely large.
To deal with this smooth switching, the present invention provides the following information code which can coexist with the other monochromatic information code.
That is, the present invention provides the information code having a display pattern formed by arranging three or more types of display areas in the same arrangement as in one of other information codes which are monochromatically displayed, the display areas being different in reflected or radiated wavelength characteristic, wherein the wavelength characteristics of the display areas in the arrangement are combined to form a unit for displaying information, characterized in that the information code has a framework defining a relationship between a combination of the wavelength characteristics of the display areas in the arrangement and information items represented thereby, the framework being designed to include a framework for monochromatically displaying information, defined by the one of the other information codes.
Unlike the monochromatic information code, the above described information code of the present invention is formed by the three or more types of display areas which are respectively different in reflected or radiated wavelength characteristic, and therefore it is necessary to discriminate the difference when reading.
A reader for the information code includes two types thereof, i.e. (a) a reader using white light as a light source, and (b) a reader using monochromatic light such as a laser source.
The reader using the white light as the light source, for reading the information code is comprised of a filter for separating reflected light or radiated light from the information code according to a difference in wavelength band, the information code being formed by arranging three or more types of display areas in a predetermined arrangement, the display areas being different in reflected or emitted wavelength characteristic,
a plurality of detectors for photo-electrically converting light in every wavelength band separated by the filter,
a plurality of determination circuits for determining whether an output from each of the detectors exceeds a predetermined determination level, and
a decoder for decoding information displayed by the information code, based on a combination of the outputs from the determination circuits, and outputting the information decoded.
The reader using the monochromatic light sources such as the laser light, for reading the information code is comprised of a plurality of monochromatic light sources provided so as to correspond to the information code being formed by arranging three or more types of display areas in a predetermined arrangement, the display areas being different in reflected or radiated wavelength characteristic, and so as to correspond to the different wavelength characteristics of the display areas, a driving circuit for light-emitting the monochromatic light source by timesharing, a detector for photo-electrically converting the reflected light or the radiated light from the information code, a determination circuit for fetching an output from the detector at every wavelength band component in synchronization with a driving signal from the driving circuit, determining whether the output at the every wavelength band component exceeds a predetermined determination level, and further determining which wavelength band component is included in the output, based on the determination, and a decoder for decoding information displayed by the information code, based on a combination of outputs from the determination circuit, indicative of respective colors of emitted light, to thereby output a decoding result.
In place of the above-mentioned determination circuit, an A/D converter for converting the output from the detector at every wavelength band component into a digital value may be used, and the decoder may be one which compares a ratio of a received light quantity of each color of emitted light, output from the A/D converter with a previously registered ratio of a received light quantity of the each color, and determines a bar color as a color having a closest ratio. As a result, multicolored barcodes can be read by using the three monochromatic light sources.
According to a first aspect of the invention, the displayable information quantity can be increased by coating the display areas forming the information code with three or more colors. As a result, many inconveniences imposed by the lack of the displayable quantity by the conventional information code can be overcome. Further, by making full use of an information mass displaying function realized by the invention, the information code becomes applicable to new fields.
According to a second aspect of the invention, a framework of the relationship between a combination of the wavelength characteristics of the respective display areas in the arrangement of the color code and displayed information items is designed to include a framework for displaying information defined by the other monochromatic information code. In this information code, the number of information items allotted to the framework for monochromatically displaying information is considerably small relative to the entire number of displayable information items according to the invention. As a result, switching from the other information code to the information code of the invention can be smoothly carried out without impairing a characteristic of the invention that the quantity of displayable information can be increased.
According to a third aspect of the invention, there is provided a reader for the color barcode of the invention, using a white light source. As a result, actual use of the color barcode can be implemented.
According to a fourth aspect of the invention, a light receiver and a processing circuit for an output therefrom can be shared by employing timesharing method. As a result, the construction of a light receiving side of the reader can be simplified.
According to a fifth aspect of the invention, a ratio of a received light quantity of each color is compared with a previously registered ratio of a received light quantity of each color. As a result, the multicolored barcode can be read by three monochromatic light sources.